Electronic digital weighing apparatus

ABSTRACT

An electronic digital weighing apparatus comprising a weight detecting section for detecting the weight of an object as an analog quantity and an analog-digital converter for converting the analog quantity to a digital quantity. The digital quantity is counted by an UP-DOWN counter the contents of which are drawn out in serial form. A unit price per unit weight of an object weighed is read into a unit price register. The serial output representing the contents of the UP-DOWN counter and the contents of a price register are added by the same number of times as the numerals stored in the unit price register. The results of the addition are introduced into the price register, and the serial output representing the contents of the UP-DOWN counter, and the contents of the unit price register and price register are indicated in digits.

United States Patent [1 1 Takahashi et al.

[451 June 19, 1973 ELECTRONIC DIGITAL WEIGI'IING APPARATUS -D CONVERTER W-REGISTER LSD P- REGlSTER ELSD KEYBOARD PULSE TIMING SlGNAL D E TECTO R 24 COUNTER I I 4/1972 l/l97l Konisi et al 235/l5l.33 Allen et al. 235/l5l.33

Primary ExaminerMalcolm A. Morrison Assistant Examiner.lames F. Gottman Attorney-Kemon, Palmer & Estabrook 57 ABSTRACT An electronic digital weighing apparatus comprising a weight detecting section for detecting the weight of an object as an analog quantity and an analog-digital converter for converting the analog quantity to a digital quantity. The digital quantity is counted by an UP- DOWN counter the contents of which are drawn out in serial form. A unit price per unit weight of an object weighed is read into a unit price register. The serial output representing the contents of the UP-DOWN counter and the contents of a price register are added by the same number of times as the numerals stored in the unit price register. The results of the addition are introduced into the price register, and the serial output representing the contents of the UP-DOWN counter, and the contents of the unit price register and price register are indicated in digits.

15 Claims, 27 Drawing Figures 22 DECIMAL CORR ECTOR 80.133138 .LlOlCl PRINTER CoNTTRoL Patented June 19, 1973 18 Shoots-Sheet 3 F a. 1A 9 2* 2 LP-DONN COUNI'ER PARNLEL-SERIALGJNVERTER DATA SELECTOR ADDITION 5 FULL 10 BINARY ADDER DECIMAL- g P REGISTER coRREcToR F l G 3A 42 UNIT PRICE WEIGHT 0000 8 Patented June 19, 1973 18 Sheets-Sheet 3 Patented June 19, 1973 3,740,536

18 Sheets-Sheet 42 FIG 3 ooooo WEIGHT 0000 a UNIT PRICE 0 o 0 '4 L/ g 9- m A I} I M f; I

Patented June 19, 1973 3,740,536

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Patented June 19, 1973- 18 Sheets-Sheet 7 W 5 m mm 3 LK 5 5. 8 0m m E 6 mu r mobikzmmwmma M33 :0 mm mm 2 PM meikzwmwmma m3 mm mm m 0 m Patented June 19, 1973 18 Sheets-Sheet 8 FIG. 6

AT dd n "A n n n H "V n M n l D "H "V p L n Vuim firm a e Mm A 8 mm Mm am m w Patented June 19, 1973 3,740,536

18 Sheets-Sheet 9 a FIG.7 E

TIME

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18 Sheets-Sheet 14- FIG. 14

TO W REGISTER INPUT GATE F l G. 15 17 44\CLEAR UREGlSTER Patented June 19, 1973 18 Shoots-Sheet 15 FIG. 16

R E T N w C O m P U 177 "U REGISTER F l G. 17

Patented June 19, 1973 3,740,536

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POOOOOO 010020 DATA g G W 012 3 SELECTOR U 012 -ELEC OR POOOO14-P'C1OC24 L DATA SELECTOR Patented June 19, 1973 18 Sheets-Sheet 1'? kw 8 m n6 a m M m w mow 7 8. m9 J mom 5 HWY na m W TN v m 2% NQQM NI I I I I IIWI J mW L wow MK 0 mN NA. 3* m9 w 75 I J I IIII A Z 1 BM m m Imfll r I I I I i I I I I I I I I l I IIIIIL 9 w w k 8 N? m $5.85 3 m M 2m n0 M R: d EN m H mm m? w n 9 M .NM. 4. V v i V m m m w m m 3 I Patented June 19, 1973 3,740,536

18 Sheets-Sheet 1 8 cpT- i 01111 FIG2O 21011 FI.G.21

-- UP-DOWN COUNTER PARALLEL- SERIAL CONVERTER TARE DETECTOR 15 WREGISTER R 23: 9 ADDE DISPLAY GATE P REGISTER ELECTRONIC DIGITAL WEIGHING APPARATUS This invention relates to an electronic digital weighing apparatus capable of indicating the weight of an object and a price arrived at by multiplying the weight by a unit price per unit weight of the object.

Where a weighing apparatus indicating the price of a weighed object by multiplying its total weight by a unit price per unit weight thereof uses a counter type multiplication circuit, the circuit arrangement becomes complicated. The counter type multiplcation circuit is so designed that a multiplicand is repeatedly added up by the same number of times as the numeral of a multiplier, and when multiplication is fully conducted up to the number of times equal to the numeral of the multiplier, then operation is stopped. Accordingly, the counter type multiplication circuit requires a device for generating a command to stop multiplication when there is reached the number of times the multiplication should be performed. Where there have to be handled numbers having many places, multiplication is repeated many times, with the resultant retardation of operation.

It is accordingly the object of this inventon to provide a weighing apparatus capable of prominently accelerating the speed at which the weight of an object is multiplied by a unit price per unit weight thereof by means of a simplified circuit arrangement.

According to an aspect of this invention, there is provided an electronic digital weighing apparatus comprising means for detecting the weight of an object in the form of an analog quantity; means for converting the analog quantity to a digital quantity; and UP-DOWN counter for counting said digital quantity; a parallelserial converter for converting the content of said counter in serial form; meansfor setting the unit price of the object; a unit price register for storing data from said unit price setting means; a price register; means for adding together output of said parallel-serial converter and the content of said price register and having the results of addition stored in said price register; means for digitally indicating output of the parallel-serial converter and the contents of said price register and unit price register; and means for performing addition a number of times equal to the content of said unit price register including a first counter for counting the number of additions; a zero detector and coincidence circuit for generating a control signal where the least significant digit ofsaid unit price register is zero or where it coincides with the content of said first counter; means for generating a shift signal so as to cause in response to said control signal the contents of said price register and unit price register to be shifted by one place; and a second counter responsive to the shift signal to be counted up to generate a signal to stop addition when the content thereof attains a predetermined value; said first counter being reset by the shift signal and said second counter being reset by a signal obtained according to the digital quantity.

This invention can be more fully understood from the following detailed description when taken in conjunction with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram of an electronic digital weighing apparatus according to this invention;

FIG. 1A is a partial modification of FIG. 1;

FIG. 2 represents the wave forms of various timing signals;

FIGS. 3A and 3B are external views of the weighing apparatus of the invention;

FIGS. 4A to 4E indicate the arrangement of the weight detector of FIG. 1;

FIG. 5 shows the circuit arrangement of the analogdigital converter of FIG. 1;

FIG. 6 indicates the wave forms of signals by way of illustrating the operation of the converter of FIG. 5;

FIG. 7 schematically illustrates the operation of a Schmitt circuit; y

FIG. 8 is a partial modification of the circuit arrangement of FIG. 5;

FIG. 9 shows the wave forms of signals by way of illustrating the operation of the modified circuit arrange ment of FIG. 8;

FIG. 10 represents the circuit arrangement of part of the UP-DOWN counter of FIG. 1;

FIG. 11 shows the circuit arrangement of the other part of the UP-DOWN counter of FIG. 1;

FIG. 12 indicates a circuit for causing the UP-DOWN counter to count absolute values;

FIG. 13 illustrates a circuit for causing the UP- DOWN counter to be reset when its contents represent the weight of a tare attached to an object;

FIG. 14 is a circuit diagram of the parallel-serial converter of FIG. 1;

FIG. 15 'is a circuit diagram of the keyboard section of FIG. 1;

FIG. 16 is a circuit diagram of the reset circuit of FIG. 1;

FIG. 17 is a circuit diagram of the binary-decimal corrector;

FIG. 18 is a chart illustrating the method of multiplication conducted by the weighing apparatus of this invention;

FIG. 19 is a diagram of the control circuits of FIG. 1;

FIG. 20 shows the condition of outputs from the counters of FIG. 19; and

FIG. 21 is a modification of the circuit of FIG. 13.

FIG. 1 is a block diagram of an electronic digital weighing apparatus according to this invention. Reference numeral 11 is a weight detector for detecting the weight of an object. As later detailed, the weight detector 11 has a rotary disk perforated with a plurality of slits at an equal space around the periphery and detects the weight of an object by rotating the disk by an angle corresponding to the weight of the object and by de tecting or counting the number of slits falling within the angle of rotation. The detection of slits is effected by co-operation of a light source and photoelectric conversion elements disposed on the opposite sides of the slits of the disk.

An electronic digital weighing apparatus according to this invention causes a pair of output pulses electrically displaced in phase from each other to be produced out of a pair of photoelectric conversion elements. The paired pulses displaced 90 in phase are supplied to an analog-digital converter 12 (hereinafter referred to as an A-D converter") to be amplified and shaped. In the A-D converter there are generated by logical circuit count up pulses (hereinafter referred to as CU pulses) and count down pulses (hereinafter referred to as CD pulses) to be supplied to an UP- DOWN counter 13. The CU pulses are produced when the slitted disk makes a normal rotation in weighing an object to cause the UP-DOWN counter 13 to count up. The CD pulses are generated when the slitted disk 

1. An electronic digital weighing apparatus having means for detecting the weight of an object in the form of an analog quantity; means for converting the analog quantity to a digital quantity; an UP-DOWN counter for counting said digital quantity; a parallel-serial converter for converting the content of said counter in serial form; means for setting the unit price of the object; a unit price register for storing data from said unit price setting means; a price register; means for adding together output of said parallel-serial converter and the content of said price register and having the results of addition stored in said price register; means for digitally indicating output of the parallel-serial converter and the contents of said price register and unit price register; and means for performing addition a number of times equal to the content of said unit price register including a first counter for counting the number of additions; a zero detector and coincidence circuit for generating a control signal where the least significant digit of said unit price register is zero or where it coincides with the content of said first counter; means for generating a shift signal so as to cause in response to said control signal the contents of said price register and unit price register to be shifted by one place; and a second counter responsive to the shift signal to be counted up to generate a signal to stop addition when the content thereof attains a predetermined value; said first counter being reset by the shift signal and said second counter being reset by a signal obtained according to the digital quantity.
 2. A weighing apparatus according to claim 1 wherein output of said parallel-serial converter is stored in a weight register.
 3. A weighing apparatus according to claim 1 wherein means for detecting the weight of the object in the form of an analog quantity and means for converting the analog quantity to a digital quantity comprise a disk having a plurality of slits bored around the periphery so as to make an angular rotation according to the weight of the object; a source of light facing the slitted portion of said disk; a pair of photoelectric conversion elements facing said light source with said slitted portion of the disk interposed therebetween, said a pair of photoelectric conversion elements being positioned in such a manner that when one photoelectric conversion element has its center disposed at the center of the disk slit, the other photoelectric conversion element has its center aligned with the side edge of the same disk slit or that of the adjacent disk slit; a pair of amplifiers for respectively amplifying electrical signals from the paired photoelectric conversion elements; first and second shaping means for shaping the wave forms of outputs from said paired amplifiers; and means for generating count up pulses for causing the UP-DOWN counter to count up according to outputs from the paired shaping means and count down pulses for causing said counter to count down according to said outputs.
 4. A weighing apparatus according to claim 3 wherein the width of the individual slits formed in said disk and a space therebetween are equal to the light receiving surface of said photoelectric conversion elements.
 5. A weighing apparatus according to claim 3 wherein said means for generating count up and count down pulses comprises a first differentiator; a series connection of a first inverter and a second differentiator, said first differentiator and said series connection being connected to said first shaping means; a second inverter connected to said second shaping means; and four AND gates, first AND gate being connected to said first differentiator and said second inverter, second AND gate being connected to said series connection and said second shaping means, third AND gate being connected to said first differentiator and said second shaping means, and fourth AND gate being connected to said series connection and said second inverter, thereby producing said count up pulses by combination of outputs of said first and second AND gates and said count down pulses by combination of outputs of said third and fourth AND gates.
 6. A weighing apparatus according to claim 3 wherein said means for generating count up and count down pulses comprises a first differentiator connected to said first shaping means; a first inverter connected to said first shaping means; a second differentiator connected to said first inverter; a third differentiator connected to said second shaping means; a second inverter connected to said second shaping means; a fourth differentiator connected to said second inverter; and eight AND gates, first AND gate being connected to said first differentiator and said second inverter, second AND gate being connected to said second differentiator and said second inverter, third AND gate being connected to said second differentiator and said second shaping means, fourth AND gate being connected to said first differentiator and said second shaping means, fifth AND gate being connected to said third differentiator and said first shaping means, sixth AND gate being connected to said first shaping means and said fourth differentiator, seventh AND gate being connected to said first inverter and said fourth differentiator, and eighth AND gate being connected to said first inverter and said third differentiator, thereby producing said count up pulses by combination of outputs of said first, third, fifth and seventh AND gates, and said count down pulses by combination of outputs of said second, fourth, sixth and eighth AND gates.
 7. A weighing apparatus according to claim 3 which further includes minute adjusting means for rotating the slitted disk to an extremely small extent so as to bring the center of one of said paired photoelectric conversion elements into alignment with the center of the disk slit; and an indicating means connected to one of said paired amplifiers so as to detect the relative positions of said one photoelectric conversion element and said disk slit.
 8. A weighing apparatus according to claim 3 wherein said paired shaping means are Schmitt circuits at least one of which has hysteresis characteristics.
 9. A weighing apparatus according to claim 1 wherein said UP-DOWN counter comprises means for detecting its zero content; and means, when actuated by output of said detecting means and count up pulse, for cauSing said UP-DOWN counter to count up by count up pulses and count down by count down pulses and when actuated by output from said detecting means and count down pulse, for causing said UP-DOWN counter to count up by count down pulses and count down by count up pulses.
 10. A weighing apparatus according to claim 1 wherein, in case said unit price register has an N number of digits, said second counter generates a read-in instruction when its content is 0, a multiplication instruction when its content is 1, and a multiplication stop instruction when its content is N+1.
 11. A weighing apparatus according to claim 1 wherein said signal generated according to the digital quantity is obtained by supplying said digital quantity to a timer circuit, thereby causing said second counter to be released from its reset condition in a certain length of time after extinguishment of said digital quantity.
 12. A weighing apparatus according to claim 1 which further includes a memory key for preventing said signals generated according to said digital quantity from being conducted to said second counter, thereby enabling the second counter to maintain its predetermined content.
 13. A weighing apparatus according to claim 1 which further includes means for detecting that the content of said UP-DOWN counter originates with error; and means for supplying reset pulses to said UP-DOWN counter in response to output of said detecting means so as to clear the content of said UP-DOWN counter.
 14. A weighing apparatus according to claim 1 which further includes means for clearing the content of said unit price register and that of said UP-DOWN counter when the power source is actuated and for clearing the content of said UP-DOWN counter when the weight of a tare is deducted.
 15. A weighing apparatus according to claim 1 which further includes means for detecting that the content of said UP-DOWN counter represents the weight of a tare; and means for clearing the content of said price register in response to output of said detecting means. 